Most of the time, the windowless building with the dome-shaped roof will be a typical high school gymnasium filled with cheering fans watching basketball and volleyball games.But come hurricane season, the structure that resembles a miniature version of the famed Astrodome will double as a hurricane shelter, part of an ambitious storm-defense system that is taking shape along hundreds of miles of the Texas Gulf Coast.

FEMA is paying for 75 percent of the dome structures, with local communities picking up the remaining cost. The funding is part of the agency’s initiative to help homeowners and communities build hardened shelters that provide protection from extreme weather.

Nationwide, more than $683 million has been awarded in 18 states, including Texas, Alabama, Michigan and South Carolina.